url: be stricter about detecting schemes
While the URL parser is very forgiving about what characters are
allowed in each component, it's useful to be strict about the scheme
so we don't accidentally interpret local paths with colons as URLs.
This restricts schemes to containing alphanumeric characters, dashes,
pluses, and dots (as specified in RFC 2396).
$ hg init
$ echo "added file1" > file1
$ echo "another line of text" >> file1
$ echo "added file2" > file2
$ hg add file1 file2
$ hg commit -m "added file1 and file2"
$ echo "changed file1" >> file1
$ hg commit -m "changed file1"
$ hg -q log
1:dfab7f3c2efb
0:c3fa057dd86f
$ hg id
dfab7f3c2efb tip
$ hg update -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg id
c3fa057dd86f
$ echo "changed file1" >> file1
$ hg id
c3fa057dd86f+
$ hg revert --no-backup --all
reverting file1
$ hg diff
$ hg status
$ hg id
c3fa057dd86f
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg diff
$ hg status
$ hg id
dfab7f3c2efb tip
$ hg update -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo "changed file1 different" >> file1
$ hg update
merging file1
warning: conflicts during merge.
merging file1 failed!
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
$ hg diff --nodates
diff -r dfab7f3c2efb file1
--- a/file1
+++ b/file1
@@ -1,3 +1,7 @@
added file1
another line of text
+<<<<<<< local
+changed file1 different
+=======
changed file1
+>>>>>>> other
$ hg status
M file1
? file1.orig
$ hg id
dfab7f3c2efb+ tip
$ hg revert --no-backup --all
reverting file1
$ hg diff
$ hg status
? file1.orig
$ hg id
dfab7f3c2efb tip
$ hg revert -r tip --no-backup --all
$ hg diff
$ hg status
? file1.orig
$ hg id
dfab7f3c2efb tip
$ hg update -C
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg diff
$ hg status
? file1.orig
$ hg id
dfab7f3c2efb tip